MISFET (Metal Insulator Semiconductor Field Effect Transistor) used, for example, in logic circuits or memories has a gate insulating film comprising a silicon oxide film formed by thermally oxidizing a silicon substrate and a gate electrode formed thereon.
Along with size-reduction and lowering of a driving voltage for semiconductor integrated circuit devices, thickness of gate insulating films for MISFET has also tends to be decreased.
However, since the decrease of the film thickness is limited, use of a high dielectric constant insulating film (high-K film) comprising a metal oxide such as Al2O3 (aluminum oxide, alumina) has been studied.
For example, Japanese Published Unexamined Patent Application No. 2000-22007 describes a semiconductor device in which the gate insulating film is comprised of a high dielectric constant insulating film.
The present inventors are under research and development of semiconductor integrated circuit devices and under study on high dielectric constant insulating films for the gate insulating film of MISFET.
However, in MISFET used for logic circuits or memories such as SRAM (Static Random Access Memory), in view of lowering for the resistance of the gate electrode and source and drain regions formed on both sides of the gate electrode, a silicide layer is formed on the regions.
Further, for fabricating the gate electrode at a high accuracy, it has been adopted for a method of patterning an insulating film (for example, silicon oxide film) on a conductive film to form a gate electrode and then fabricating the gate electrode by using such an insulating film as a mask.
Then, the insulating film used as the mask is removed for silicidation described above, but a gate insulating film on both ends of the gate electrode is also scraped and oxidation for repairing gate edge is necessary for compensating the same.
However, as will be described specifically, when the oxidation for repairing gate edge is applied in a case of using the high dielectric constant insulating film for the gate insulating film, since a silicon oxide film is formed on both ends of the gate electrode, various disadvantages may be caused such as lowering of the capacitance at the end of the gate electrode and degradation of the film quality of the high dielectric constant insulating film itself.
This invention intends to improve the characteristics of a semiconductor integrated circuit device having MISFET using a high dielectric constant insulating film for a gate insulating film.
Further, this invention intends to provide a more preferred production method by using a high dielectric constant insulating film for a semiconductor integrated circuit having MISFET using a gate insulating film.
The foregoing and other objects and novel features of the invention will be apparent by reading the description of the present specification and the appended drawings.